Implantable medical lead

ABSTRACT

A proximal end of an implantable lead may include a unitary connector pin having a socket end, a conductor end, and a necked-down portion arranged therebetween, where the conductor end includes a crimp cavity with an inner surface and a proximal end of the conductor is arranged in the crimp cavity, and a pin sleeve sleevably engaging the proximal end of the conductor and crimping the proximal end of the conductor against the inner surface, the proximal end may also include a unitary ring connector having a band portion, a notch portion, and a crimp portion where the crimp portion includes a crimp cavity with an inner surface and a proximal end of the conductor is arranged in the crimp cavity, and a ring sleeve sleevably engaging the proximal end of the conductor and crimping the proximal end of the conductor against the inner surface creating a crimp connection.

This application is a 35 USC 371 national stage of PCT PatentApplication No. PCT/CN2011/081808, filed Nov. 4, 2011, entitled“Implantable Medical Lead,” the entire contents of which is herebyincorporated by reference, in its entirety.

FIELD OF THE INVENTION

The present disclosure relates generally to implantable electricalleads. More particularly, the present disclosure relates to connectionend features of implantable electrical leads where the lead is connectedto an associated defibrillator, pacemaker, or other electricalstimulation device. Still more particularly, the present disclosurerelates to connection end features of implantable electrical leadshaving an active mechanism on a treatment end thereof.

BACKGROUND OF THE INVENTION

Electrodes are often used to stimulate contraction of the heart. Forexample, when a patient's heart is functioning with an abnormal rhythm,electrical energy may be applied to the heart via the electrodes toreturn the heart to a normal rhythm. In some cases this procedure may bean isolated event while in other cases a more frequent, regular, or evencontinuous process is used. In these cases electrodes may beincorporated into a lead that is used with a pacemaker, defibrillator,or other electrical stimulation device such that pacing pulses may bedelivered, for example, to an atrium or ventricle of a heart. The systemincluding the electrical stimulation device and the lead may beimplantable and, thus, used over long periods of time.

In general, a lead includes a pair of electrodes disposed at a distalend of the lead which may be positioned in the right ventricle or theright atrium of the heart. The proximal end of the lead may be coupledto a defibrillator or a pacemaker and conductors may deliver electricalimpulses along the length of the lead to the electrode therebydelivering pacing pulses to the heart.

There are at least two conventional types of leads. The first type ofleads is referred to as an active electrical lead with an activemechanism at the distal end. The second type of leads is referred to asa passive electrical lead with a passive mechanism at the distal end.

The distal end of a typical active electrical lead may include a helixtype fixation mechanism designed to be actuated and axially extendand/or rotate out of a tip portion of the lead to engage or embed intothe endocardium. The distal end of a typical passive electrical lead mayinclude an anchor type fixation mechanism designed to anchor the distalend in the heart. The fixation mechanism for a passive lead, forexample, may include one or more radially spaced tines that secure thedistal end in the heart.

The proximal end of pacemaker and defibrillator leads are commonlydesigned and manufactured to a standard such as YY/T 0491-2004//ISO5841-3, 2000. The standard is applicable to both active and passivepacemaker or defibrillator leads. Within that standard, medical deviceimplant companies commonly have their own unique designs. Among thetechnologies used to meet the standard, are laser welding and metalcrimping resulting in highly reliable pacemaker and defibrillator leadjoint connections.

The design of defibrillator and pacemaker leads has evolved over time.Over time and at present, the proximal end of an active electrical leadand the proximal end of a passive electrical lead are generally designeddifferently due to their functional differences. That is, the proximalend of an active lead may be designed to actuate and/or control thedistal active mechanism, while the proximal end of a passive lead maynot include such actuation and/or control features. System designs andassembly processes of the passive and active electrical leads are, thus,different. As a result, the overall cost of having significant differentsystem designs and assembly processes is relatively high and a systemhaving common features or similar or exchangeable components between anactive electrical lead and a passive electrical lead may be lessexpensive and more attractive to consumers.

SUMMARY

In one embodiment of the present application, a proximal end of a leadmay include a longitudinally extended, electrically conductive connectorpin, extending through and rotatably or fixedly disposed in a centerbore of a proximal seal and a center bore of a connector insulator. Theconnector insulator may include a reduced section which extends withinthe center bore of the proximal seal. The proximal end may also includea longitudinally extended, electrically conductive inner coil crimped tothe connector pin. The crimped connector pin and inner coil may bedisposed within the center bore of the connector insulator and theconnector pin may be electrically connected to the inner coil. Theproximal end may also include a longitudinally extended, electricallyconductive outer coil crimped to a ring connector and the ring connectormay be electrically connected to the outer coil. The proximal end mayalso include a longitudinally extended insulator tubing disposed betweenthe inner coil and the outer coil and the insulator tubing may provideelectrical insulation between the inner coil and the outer coil andelectrical insulation between the inner coil and the ring connector. Theproximal end may also include a longitudinally extended boot sealdisposed over the outer coil and the crimped outer coil and the ringconnector may be disposed within a center bore of the boot seal.

In further embodiments, the proximal seal may include a plurality ofseals to prevent fluid or other liquid from being in contact with theconnector pin and may provide electrical insulation between the ringconnector and the connector pin. Additionally in one embodiment, theboot seal may include a plurality of seals, wherein the boot sealprevents fluid from being in contact with the ring connector.

In one embodiment, an inner surface of the connector insulator mayprovide rotational bearing for the connector pin, and rotation of theconnector pin may drive rotation of the inner coil. As such, rotation ofthe pin may result in rotating a mechanism disposed at a distal end ofthe lead. Such a lead may be referred to as an active lead, and themechanism may be referred to as an active mechanism.

In another embodiment, the connector pin may be fixedly connected to aninner surface of the proximal seal by medical adhesive or otherbio-adaptable adhesive. In this embodiment, the connector pin may notcause rotation of a mechanism disposed at a distal end of the lead. Sucha lead may be referred to as a passive lead, and the mechanism may bereferred to as a passive mechanism.

In still another embodiment, a proximal end of an implantable lead maybe provided for use with a lead having a conductor. The proximal end ofthe lead may include a unitary connector pin having a socket end, aconductor end, and a necked-down portion arranged therebetween. Theconductor end may include a crimp cavity with an inner surface and theproximal end of the conductor may be arranged in the crimp cavity. Theproximal end of the lead may also include a pin sleeve sleevablyengaging the proximal end of the conductor and crimping the proximal endof the conductor against the inner surface.

In yet another embodiment, an implantable lead may include alongitudinally extended body having a proximal end and a distal end anda conductor extending from the proximal end to the distal end. The leadmay include a unitary connector pin arranged on the proximal end. Theunitary connector pin may include a socket end, a conductor end, and anecked-down portion arranged therebetween. The conductor end may includea crimp cavity with an inner surface and a proximal end of the conductormay be arranged in the crimp cavity. The lead may also include a pinsleeve sleevably engaging the proximal end of the conductor and crimpingthe proximal end of the conductor against the inner surface.

In yet another embodiment, a proximal end of an implantable lead may beprovided for use with a lead having a conductor. The proximal end mayinclude a unitary ring connector having a band portion, a notch portion,and a crimp portion. The crimp portion may include a crimp cavity withan inner surface and a proximal end of the conductor may be arranged inthe crimp cavity. The proximal end may also include a ring sleevesleevably engaging the proximal end of the conductor and crimping theproximal end of the conductor against the inner surface creating a crimpconnection.

In still another embodiment, an implantable lead may include alongitudinally extended body having a proximal end and a distal end andhaving a conductor extending from the proximal end to the distal end.The lead may also include a unitary ring connector arranged on theproximal end and having a band portion, a notch portion, and a crimpportion. The crimp portion may include a crimp cavity with an innersurface and a proximal end of the conductor may be arranged in the crimpcavity. The lead may also include a ring sleeve sleevably engaging theproximal end of the conductor and crimping the proximal end of theconductor against the inner surface creating a crimp connection.

In still another embodiment, a pair of implantable leads may include anactive lead having an active mechanism arranged on a distal end and apassive lead having a passive mechanism arranged on a distal end. Eachof the active and passive leads may include a connector insulator with acentral bore. Each of the leads may also include a connector pin havinga conductor end and a socket end. The connector pin of each lead mayextend through the central bore of their respective connectorinsulators. Each of the leads may also include a ring connector having aband portion concentrically arranged around and insulated from theirrespective conductor ends of respective connector pins and the ringconnectors may include a crimp portion. The connector insulator, theconnector pin, and the ring connector of the active lead may besubstantially the same as the respective connector insulator, connectorpin, and ring connector of the passive lead.

In still another embodiment, a connector insulator for a proximal end ofa lead may include a central body, a distal extension extending from thecentral body and having a plurality of cascading shoulders, and aproximal extension extending from the central body opposite the distalextension. The proximal extension and the central body may include afirst longitudinally extending bore for receiving a necked-down portionof a connector pin and the bore may have a first diameter. The centralbody and distal extension may include a second longitudinally extendingbore for receiving a conductor end of the connector pin and the secondbore may have a diameter larger than the first bore.

One of the advantages of the embodiments disclosed herein is that mostof the parts and components of active and passive leads can be shared.As such, while the several parts of the passive lead may be moreinvolved or complicated than other passive lead designs, the commonalitybetween the parts of the active lead and passive lead may reduce thecost of tooling, manufacturing, and assembly for a manufacturer that ismanufacturing both active and passive leads. By reducing the differencesbetween the two types of leads, the savings in manufacturing the leadsmay make up for any costs associated with a more complicated passivelead design.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a perspective view of one embodiment of an implantablemedical electrical lead with an active mechanism according to someembodiments.

FIG. 2 shows a perspective view of one embodiment of an implantablemedical electrical lead with a passive mechanism according to someembodiments.

FIG. 3 shows a cross-sectional view of a proximal end of the lead ofFIG. 1.

FIG. 4 shows a perspective view of a connector pin of the lead of FIG. 1and FIG. 2.

FIG. 5 shows a perspective view of a pin sleeve of the lead of FIG. 1and FIG. 2.

FIGS. 6A and 6B show a perspective view and a perspectivecross-sectional view, respectively, of a connector insulator of the leadof FIG. 1.

FIGS. 7A and 7B show a perspective view and a perspectivecross-sectional view, respectively, of a proximal seal of the lead ofFIG. 1.

FIGS. 8A and 8B show a perspective view and a perspectivecross-sectional view, respectively, of a ring connector of the lead ofFIG. 1 and FIG. 2.

FIGS. 9A and 9B show a perspective view and a perspectivecross-sectional view, respectively, of a ring sleeve of the lead of FIG.1 and FIG. 2.

FIGS. 10A and 10B show a perspective view and a perspectivecross-sectional view, respectively, of a boot seal of the lead of FIG. 1and FIG. 2.

FIG. 11 shows a cross-sectional view of a proximal end of the lead ofFIG. 2.

FIGS. 12A and 12B show a perspective view and a perspectivecross-sectional view, respectively, of a connector insulator of the leadof FIG. 2.

FIGS. 13A and 13B show a perspective view and a perspectivecross-sectional view, respectively, of a proximal seal of the lead ofFIG. 2.

DETAILED DESCRIPTION

The present disclosure relates, in one embodiment, to an implantableelectrical lead having an active mechanism on a distal end for engagingthe heart or other treatment site of a patient. (i.e., active lead) Inanother embodiment, the present disclosure relates to an implantableelectrical lead having a passive mechanism on a distal end. (i.e.,passive lead) Each of the active and passive leads may include a systemof parts on a proximal end thereof that is primarily adapted to connectto and electrically communicate with a defibrillator, pace maker, orother electrical stimulation device. It is noted that some of the partsmay be adapted to insulate between other parts and/or between theproximal end and the electrical stimulation device. In the case of theactive lead, a portion of the parts may be particularly adapted to allowactuation and control of the active mechanism on the distal end of thelead while others of the parts may be more generic for use with activeor passive leads. In contrast, the passive lead, while including thegeneric parts, may include a portion of parts particularly adapted torestrain relative motion of the parts and thus avoid provisions foractuation and control. In some embodiments, the systems of parts of theproximal end of the leads may be designed such that few parts differwhen comparing the parts of an active lead to the parts of a passivelead. As such, a relatively high number of parts may be the same betweenactive and passive leads.

FIG. 1 illustrates a perspective view of one embodiment of animplantable medical electrical lead 100. The lead 100 has a proximal end102 and a distal end 104. As shown, an active mechanism 106 may bedisposed at the distal end 104 and may include a helix-type fixationmechanism 108. The fixation mechanism 108 may be designed to axiallyextend out of a tip portion 110 of the lead 100 to engage a treatmentsite of a patient such as the endocardium of a heart, for example. Thehelix-type of fixation mechanism 108 may be retractably extended out ofthe tip portion 110 at the distal end 104 of the lead 100. In operation,a conductive connector pin at the proximal end 102 of the lead 100 maybe rotated to drive the active mechanism 106 at the distal end 104 ofthe lead 100, thereby extending the helix-type fixation mechanism 108out of the tip portion 110 of the distal end 104 of the lead 100. Therotating extension of the helix-type fixation mechanism 108 may causethe mechanism 108 to engage (i.e., screw into) a treatment site of apatient.

FIG. 2 illustrates a perspective view of another embodiment of animplantable medical electrical lead 400. The lead 400 has a proximal end402 and a distal end 404. As shown, a passive mechanism 406 may bedisposed at the distal end 404 and may include an anchor-type fixationmechanism 408. The fixation mechanism 408 may be designed to anchor thelead at a treatment site of a patient such as the endocardium of aheart, for example. The fixation mechanism 408 may include one or moreradially spaced tines 410 that engage the treatment site or othertissues adjacent to the treatment site thereby holding the distal end ator near the treatment site.

As shown in FIGS. 1 and 2, the lead 100 is longitudinally extendedbetween the distal end 104 and the proximal end 102, and the lead 400 islongitudinally extended between the distal end 404 and the proximal end402. It is appreciated that the primary focus of the present inventionis the proximal end 102,402 of the lead 100,400 whereas the distal end104,404 of the lead 100,400 can be of any suitable fixation mechanism asdescribed above in FIGS. 1 and 2, without departing from the principlesof the present invention. It is also appreciated that the proximal ends102,402 of the leads 100,400 are designed and arranged such that most ofthe parts or components of the leads 100,400 can be commonly used. Thatis, an overall product line or system architecture approach has beenused in the design to consider the tooling, manufacturing, and assemblyimplications of the selected designs. As a result, the designs of activeleads 100 and passive leads 400 are more similar to one another thanother active and passive leads in the art. Accordingly, the overall costof manufacturing such leads may be significantly reduced.

Referring now to FIG. 3, the proximal end 102 of the lead 100 includes asystem of parts or pieces. The system of parts or pieces may be dividedinto three categories including inner parts relating to an innerconductor, outer parts relating to an outer conductor, and insulatingparts for electrically separating the inner parts from the outer parts.The inner parts may include a conductive connector pin 112, an innerconductor or coil 120, and a pin sleeve 122. The outer parts may includea ring connector 130, an outer conductor or coil 134, and a ring sleeve136. The inner and outer parts may be substantially separated by theinsulating parts including a connector insulator 116 and an insulatortubing 124. A proximal seal 114 and a boot seal 140 may also beprovided.

Beginning with the inner parts, the connector pin 112 may be configuredfor electrical engagement with a defibrillator, pacemaker or otherelectrical stimulation device and for communicating electrical impulsesto the inner conductor or coil 120. As such, the connector pin 112 maybe adapted at one end for plugging into a socket of an electricalstimulation device and may be adapted at another end for connecting tothe inner conductor or coil 120.

A close-up view of a connector pin 112 is shown in FIG. 4. As shown, theconnector pin 112 may include a socket end 160 and a conductor end 162and may further include a necked-down portion 164 extendingtherebetween. The socket end 160 of the pin 112 may be generallyelongate and cylindrically shaped and may have a diameter adapted forplacement in a correspondingly shaped socket of an electricalstimulation device. The proximal end of the socket end 160 may include achamfered edge 166 for guiding the pin 112 into the socket when placingthe pin 112 into the electrical device. The distal end of the socket end160 may include a substantially sharp or square edge 168 for abuttingthe connector insulator 116 or the proximal seal 114 as the case may be.

With respect to exposed portions of the proximal end of the lead, likethe socket end just described, that may contact or otherwise physicallyinteract with an electrical stimulation device, these portions may bedesigned to meet industry standard specifications such as the IS-1specification, for example. As such, while particular parts of theproximal end are described herein as varying in size, diameter, length,or other dimensional variations, in some embodiments, the exposedportions of the parts may be selected to meet such specifications orstandards. However, nothing in the present disclosure should beconstrued to limit the parts to industry standard dimensions.

The necked-down portion 164 of the connector pin 112 may also begenerally elongate and cylindrically shaped an may have a diametersmaller than that of the socket end 160. The necked-down portion 164 mayhave a length selected to longitudinally secure the pin 112 relative tothe connector insulator 116 and the proximal seal 114. That is, thelength of the necked-down portion 164 may correspond to a bore length inthe connector insulator or, as shown in FIG. 11, a bore length in theconnector insulator plus a bore length in the proximal seal, such thatlongitudinal motion is substantially prevented relative to the connectorinsulator and the proximal seal. This particular aspect of the connectorpin design may contribute to allowing for the same pin 112, 412 to beused in both the active and passive lead designs. As shown in FIG. 3,the socket end 160 and the necked-down portion 164 may include alongitudinally extending bore 170 extending from the proximal end of thepin 112 to the distal end of the necked-down portion 164 and exitinginto a crimp zone 172 within the conductor end 162 of the pin 112. Thisbore 170 may be sized and adapted to receive a stylet, for example, wheninstalling or positioning the lead, or when access to the distal end ofthe lead is desired.

The conductor end 162 of the pin 112 may be substantially cylindricallyshaped with an outer diameter slightly larger than that of thenecked-down portion 164 and slightly smaller than that of the socket end160. Other relationships of diameters of the several portion of theconnector pin 112 may also be provided. For example, the conductor end162 may have an outer diameter larger than the socket end 160. In theembodiment shown, however, for example in FIG. 3, the conductor end 162may be arranged in a relatively congested area where the ring connector130, the insulator tubing 124, the connector insulator 116, theconductor end 162, the inner conductor 120, and the pin sleeve 122 alloverlap. Where the proximal end is designed to meet the IS-1specification, for example, restrictions on the overall outer diametertogether with the congestion may cause the outer diameter of theconductor end 162 to be smaller than the socket end 160. The conductorend 162 of the pin 112 may include an inner cavity or crimp zone 172having a substantially cylindrical cross-section with a diameterdefining an inner diameter of the conductor end 162. The conductor end162 may have a length selected to match or exceed the length of the pinsleeve 122, to be described below, so as to provide suitable length forcrimping the conductor 120. Other conductor end lengths may be selectedand a suitable length of the cavity 172 may be selected to ensuresufficient crimp length of the coil 120 within the cavity 172. Theconductor end 162 may include a hole or a pair of holes 174 forinspecting the crimped conductor 120 within the cavity 172. The holes174 may extend through the conductor end 162 from an outer surface andinto the cavity 172 and may be positioned near a proximal end of thecavity 172. As such, when the conductor 120 is crimped in the cavity172, a portion of the conductor 120 may be visible through the hole orholes 174 and the depth into the cavity 172 of the crimp connection maybe ascertainable to assure sufficient crimp length.

The connector pin 112 can be made from one or more of severalbiocompatible conductor materials such as stainless steel 316L or ametal alloy MP35N, for example. The pin material may be selected to bebiocompatible and suitably conduct and transmit electrical signals froman electrical stimulation device. The material together with the sizesof the pin 112 and the pin sleeve 122 (e.g., relative diameters and wallthicknesses) may be selected to suitably crimp the inner conductor orcoil 120 therebetween such that a reliable crimp connection is providedthat is both mechanically secure and through which electricaltransmissions can be made. It is noted that the connector pin 112 may beengineered to have sufficient strength to withstand compression forcesassociated with assembly. For example, as can be appreciated from FIG.3, the conductor end 162 of the pin 112 may be forced through the bore118 of the connector insulator 116 into the bore 119 and the necked downportion 164 of the pin 112 may be suitably strong to withstand such acompression force without buckling or weakening. In an effort to moresmoothly insert the pin 112, the distal end of the conductor end 162 mayinclude an exterior taper 176 as shown in FIG. 4.

A close-up view of the pin sleeve 122 is shown in FIG. 5. The pin sleeve122 may be adapted for insertion a selected distance into the proximalend of the conductor or coil 120. As such, the pin sleeve 122 mayinclude a sleeve portion 178 and a flare portion 180. The sleeve portion178 may be substantially cylindrically shaped for insertion into theproximal end of the coil 120. The diameter of the sleeve portion 178 maybe slightly larger than that of the coil 120 to create some connectingfriction between the sleeve 122 and the coil 120 when the coil issleeved over the sleeve portion 178. The diameter of the pin sleeve 122may also be selected to suitably pinch or press the coil 120 against theinner surface of the cavity of the conductor end 162 of the pin 112 whencrimping the coil 120. The sleeve portion 178 may have a length selectedto sufficiently engage the coil 120 and hold the coil 120 when the coil120 is crimped between the sleeve 178 and the inner surface of theconductor end 162 of the pin 112. The flare portion 180 of the sleeve122 may be positioned on a proximal end of the sleeve 122 and may beconfigured to limit or stop the insertion distance of the sleeve 122 inthe coil 120 and to prevent the sleeve 122 from passing too far into thecoil 120 when crimping the coil 120. As such, the flared portion 180 mayinclude a gradually increasing diameter beginning with the diameter ofthe sleeve portion 178 and extending to a diameter approximating theinner diameter of the conductor end 162 of the pin 112. It is noted thatthe proximal end of the pin sleeve 122 is shown as a flared portion incontrast to the more square or flange-like proximal end on the ringsleeve 136 of FIGS. 9A and 9B. The shape of the proximal ends of theseparts 122, 136 may be selected based on whether the respective part isformed from tubing or bar stock. For example, if the part is formed fromtubing, the proximal end may be flared like the pin sleeve 122 shown.However, if the part is formed from bar stock, the proximal end may beflange-like like the ring sleeve 136. Other fabrication techniques andapproaches may also be used.

The inner diameter of the conductor end 162 of the pin 112 and the outerdiameter of the sleeve portion 178 of the pin sleeve 122 may be selectedto suitably crimp the inner conductor or coil 120 therebetween. Forexample, the pin sleeve 122 may have an outer diameter and the wire usedfor the inner coil 120 may have a thickness. The inner diameter of thecavity 172 may be selected to be slightly less than the outer diameterof the pin sleeve 122 plus twice the wire thickness. As such, when thepin sleeve 122 is inserted into the coil 120 and the pin sleeve 122 andconductor 120 are pressed into the cavity 172 of the conductor end 162of the pin 112, the coil 120 may be crimped between the pin sleeve 122and the inner surface of the cavity 172 of the conductor end 162 of thepin 112. Consideration may be given to the thicknesses and elasticity ofthe conductor end 162 of the pin and the sleeve 122 when selectingsuitable relative diameters.

The inner conductor or coil 120 may be an electrically conductive memberextending longitudinally along the lead 100. The conductor 120 may be inthe shape of a coil or a tubular sleeve shape may be provided. The coilshape may provide flexibility to the lead and allow for maneuverabilitywhen placing the lead, for example. The inner conductor 120 may includea longitudinally extending bore along its length for receiving a styletor other device.

As mentioned, the inner parts may be electrically isolated from theouter parts by a system of insulating parts. A close-up view of theconnector insulator 116 is shown in FIGS. 6A and 6B. The connectorinsulator 116 may be configured for sleevably isolating the connectorpin 112 and a portion of the inner conductor 120 from the outer parts.In addition, the connector insulator 116 may be configured forsupporting all or a portion of the proximal seal 114. In this activelead embodiment, the connector insulator 116 may be configured forrotationally isolating the connector pin 112 from the proximal seal 114such that the connector pin 112 may be rotated thereby rotating theinner conductor or coil 120 and controlling an active mechanism 106 on adistal end 104 of the lead 100.

As shown in FIGS. 6A and 6B, the connector insulator 116 may include acentral body 182, a proximal extension 184, and a distal extension 186.The central body 182 may include a substantially cylindrically shapedbody having an outer diameter. The distal extension 186 may also besubstantially cylindrically shaped and may include an outer diametersmaller than that of the central body 182. The distal extension 186 mayextend from the central body 182 in the distal direction from a set ofcascading shoulders. An outer shoulder 188 may include a portion of theouter surface 129 of the central body 182 and a step surface 132 havinga width. The width of the step surface 132 may define a diameter of acylindrical inner shoulder surface 127 where the diameter of the innershoulder surface 127 is less than the diameter of the central body 182but larger than the diameter of the distal extension 186. The innershoulder 190 may thus include this inner shoulder surface 127 and anadditional step surface 128 having a width. The width of the additionalstep surface 128 may define the diameter of the distal extension 186.The distal tip of the distal extension 186 may include a tapered orchamfered tip 192 creating a conical shape for receiving the clawportion 126 of the insulator tubing 124. That is, as shown in FIG. 3,for example, the claw portion 126 of the insulator tubing 124 may bestretched, expanded, or otherwise distended over the distal extension186 of the connector insulator 116. This relationship of the distendedclaw portion 126 being held away from the crimp connection of the innerconductor 120 may provide space for this connection and may help toavoid binding, pinching, or otherwise constricting the crimp connectionat this location. As such, in the case of an active lead, the innerparts including the connector pin 112, the pin sleeve 122, and the innerconductor 120 may be free to rotate relative to the remaining partswithout restriction.

The proximal extension 184 of the connector insulator 116 may extendfrom the proximal end of the central body 182 and may be substantiallycylindrical with a diameter smaller than that of the central body 182.The transition between the central body 182 and the proximal extension184 may define a proximal shoulder 194 opposite the cascading shouldersdescribed. The outer surface of the proximal extension 184 may includeone or more circumferential grooves 196. The proximal extension 184, inthis active embodiment, may have a length substantially equal to thelength of the proximal seal 114. As such, when the proximal seal 114 ispositioned on the proximal extension 184 a distal end of the proximalseal 114 may abut the proximal shoulder 194 of the central body 182 anda proximal end of the proximal seal 114 may align with the proximal endof the connector insulator 116.

The connector insulator 116 may include center bore 118 with a diameterconfigured for receiving the necked-down portion 164 of the connectorpin 112. The diameter of the bore 118 may be slightly larger than thenecked-down portion 164 so as to allow rotation of the connector pin 112relative to the connector insulator 116. In other embodimentslubrication and/or a bushing may be provided to offer further rotationalfreedom of the pin 112 relative to the connector insulator 116. Thecenter bore 118 may extend from the proximal end of the insulator 116 toa point within the central body 182 of the insulator 116 where thecenter bore 118 may transition to a bore 119 with a larger diameter. Thebore 119 with the larger diameter may accommodate the increased diameterof the conductor end 162 of the connector pin 112. The diameter of thebores 118, 119 may remain slightly larger than the respective portion ofthe connector pin 112 to allow rotation of the connector pin 112relative to the connector insulator 116. The bore 119, with its largerdiameter, may extend through the remaining portion of the central body182 and through the distal extension 186 of the connector insulator 116.

The connector insulator 116 may be constructed from a bio-compatiblegrade of insulator material. This material may be selected to providesufficient mechanical strength, elasticity, and insulationcharacteristics. For example, as described with respect to the connectorpin 112, the conductor end 162 of the connector pin 112 may be pressedthrough the bore 118 of the connector insulator 116. As such, theconnector insulator 116 may be made of a relatively strong yet elasticmaterial allowing the pin 112 to be driven therethrough without loss ofstrength and without permanent deformation. In some embodiments, theconnector insulator 116 may be made from a moldable thermoplastic suchas polyurethane, polysulfone, or PEEK. Still other material may beselected to provide the suitable strength, elasticity, and insulationcharacteristics. While elastic, the connector insulator 116 may also bedesigned to secure the connector pin 112 and prevent the connector pin112 from being removed or withdrawn from the proximal end of the lead100. That is, a proximal shoulder 131 at the proximal end of theconductor end 162 may be provided to transition to the smaller diameternecked down portion 164. A surface 135 of the shoulder 131 may interactwith an opposing surface 137 of shoulder 133 on the interior surface ofthe connector insulator 116. The shoulder 133 on the interior of theconnector insulator 116 may be formed as the transition between the bore118 and bore 119. The relative diameters of the necked down portion 164and bore 118 and the relative diameters of the conductor end 162 andbore 119 may be selected to allow the connector pin 112 to rotate withinthe connector insulator 116. However, to prevent removal therefrom, thediameter of the conductor end 162 may be selected to be larger than thediameter of bore 118. In addition, the material of connector insulator116 may be selected to be rigid enough to prevent withdrawal of theconnector pin 112 under withdrawal loads or strengths specified by theIS-1 specification, for example.

The proximal seal 114 may be configured for secured placement on theconnector insulator 116 and for sealingly engaging a socket on anelectrical stimulation device. In addition, the proximal seal 114 mayfunction, together with the connector insulator 116, to electricallyisolate and prevent crosstalk between the ring connector 130 and theconnector pin 112. As shown in FIGS. 7A and 7B, the proximal seal 114may include a flushing portion 198 and a sealing portion 200. Theflushing portion 198 may be distal to the sealing portion 200 and mayfunction to encompass the connector insulator 116 and abut the centralbody 182 thereof. The flushing portion 198 may be substantiallycylindrical with an outer diameter substantially matching the outerdiameter of the central body 182 thereby being flush therewith. Thesealing portion 200 may be proximal to the flushing portion 198 and mayalso be substantially cylindrical with an outer diameter slightlysmaller than the flushing portion 198. The sealing portion 200 mayinclude one or more (e.g., two) circumferentially extending ribs 146protruding from the outer surface of the sealing portion 200. The ribs146 may extend from the sealing portion 200 such that the outer surfaceor tip of the ribs 146 defines a diameter larger than the flushingportion 198. The ribs 146 may be adapted to engage a cylindrical socketand may have an outer diameter at least slightly larger than thediameter of the socket so as to sealingly engage an inner surface of thesocket and prevent fluids or other matter from traveling into the socketand reaching the connector pin 112 or otherwise leaking into theelectrical stimulation device.

The proximal seal 114 may include a bore 150 extending from its proximalend to its distal end and the diameter of the bore 150 may besubstantially equal to the outer diameter of the proximal extension 184of the connector insulator 116. In some embodiments, the proximal seal114 may be made of a resilient material and the bore diameter may beslightly smaller than the outer diameter of the proximal extension 184of the connector insulator 116 such that the proximal seal may bestretched to receive the connector insulator 116 thereby compressivelyreceiving the connector insulator 116 therein. The proximal seal 114 maybe made from a suitably resilient material to compressively seal theproximal end 102 of the lead 100 with the electrical stimulation device.In some embodiments, the seal 114 may be a biocompatible silicone, forexample. Still other materials may be selected to suitably seal theproximal end 102 of the lead 100 with the electrical stimulation deviceand also be compatible with the body.

The insulator tubing 124 shown in FIG. 3 may function to electricallyisolate portions of the inner parts from the outer parts. Along someportions of the lead, the insulator tubing 124 may function togetherwith the connector insulator 116 to provide the electrical isolation. Asshown, a portion of each of the inner parts including the connector pin112 (i.e., the conductor end 162 thereof), the inner coil 120, and thepin sleeve 122 may be separated from the outer parts by the innerinsulator tubing 124. Near the proximal end of the conductor 120, thedistal extension 186 of the connector insulator 116 also isolates theseelements. The insulator tubing 124 may be substantially tube-like inshape defining an inner lumen having a diameter slightly larger than theouter diameter of the inner conductor or coil 120. As such, in the caseof an active lead, the inner conductor 120 may be relatively free torotate within the insulator tubing 124. The insulator tubing 124 may bemade of an insulating material so as to electrically isolate theenclosed components or features from the components or features outsidethe tubing 124. The insulator tubing 124 may include a flared or clawportion 126 at its proximal end for receiving the distal extension 186of the connector insulator 116. In some embodiments, this portion is aflared or expanded to fit over the distal extension 186 of the connectorinsulator 116. As previously mentioned, this flared or claw portion 126held open by the distal extension 186 of the connector insulator 116 mayhelp to prevent binding of the inner parts by providing space for thecrimp connection. Within the distal extension 186 of the connectorinsulator 116, the conductor end 162 of the pin connector 112, the pinsleeve 122, and the proximal end of the conductor or coil 120 may bearranged and thus electrically isolated from components or featuresoutside the claw portion 126.

Having described the inner parts and the isolation thereof by theinsulator tubing 124 and the connector insulator 116, the outer partsmay now be described. As shown in FIG. 3, the outer part may include thering connector 130, an outer conductor or coil 134, and a ring sleeve136.

The ring connector 130 may be configured to provide an exposed surfacefor electrical communication with an electrical stimulation device. Thering connector 130 may also be configured for axially and rotationallysecuring the outer parts to the the connector insulator 116.

A close-up view of the ring connector 130 is shown in FIGS. 8A and 8B.The ring connector 130 may include a band portion 204, a slot portion206, and a crimp portion 208. The band portion 204 may form an exposedconductive band near the proximal end 102 of the lead 100 that is distalto the connector pin 112. The band portion 204 may be configured forelectrical communication with a portion of a socket of an electricalstimulation device and the diameter of the band portion 204 may beselected to suitably engage electrical conductors within the socket.

The band portion 204 may include a substantially cylindrical shape withan outer diameter matching that of the central body 182 of the connectorinsulator 116. The band portion 204 may include an inner cavity 210configured to receive the distal extension 186 of the connectorinsulator 116. More particularly, the inner cavity 210 of the bandportion 204 may have a diameter substantially equal to or slightlysmaller than the outer diameter of the cylindrical inner shouldersurface 127 on the connector insulator 116. As such, the band portion204 may be sleeved over the claw portion 126 positioned on the distalextension 186 and may frictionally engage the cylindrical inner shouldersurface 127 to secure the ring connector 130 to the connector insulator116. In this manner, the concentric assembly of the several parts of thesystem may be maintained. The band portion 204 of the ring connector 130may thus and abut the step surface 132 causing the outer surface of theband portion 204 to be flush with the central body 182 of the connectorinsulator 116. The band portion 204 may have a length slightly greaterthan the length of the distal extension 186 of the connector insulator116.

The slot portion 206 of the ring connector 130 may be arranged distallyrelative to the band portion 204 and may be substantially cylindricallyshaped with a diameter smaller than the band portion 204. The slotportion 206 may be configured for encroaching on the insulator tubing124 and, as such, the slot portion 206 may include an inner diametersimilar to or slightly larger than the outer diameter of the insulatortubing 124. The smaller outer diameter of the slot portion 206 may allowfor an inwardly projecting rib 212 from the boot seal 140 to nest in theslot 206 formed thereby. The rib 212 may be held in positionlongitudinally by two opposing surfaces 142 and 143. The slot portion206 may include one or more holes 214 for placement of adhesive tosecure the ring connector 130, the insulator tubing 124, and the bootseal 140 together.

The crimp portion 208 may be arranged distally to the slot portion 206and may be substantially cylindrically shaped with an outer diameterlarger than the slot portion 206 and smaller than the band portion 204.Like the conductor end 162 of the connector pin 112, the crimp portion208 of the ring connector 130 may be configured for crimping of theouter conductor 134 therein. As such, the crimp portion 208 may define acrimp zone or cavity 216 therein. The cavity or crimp zone 216 mayinclude an inner diameter selected in conjunction with the ring sleeve136 to suitably crimp the outer conductor 134 therein. That is, the ringsleeve 136 may have an outer diameter and the outer conductor 134 mayinclude a wire thickness. The inner diameter of the crimp zone or cavity216 may be selected to be equal to or slightly smaller than the outerdiameter of the ring sleeve 136 plus twice the wire thickness, forexample. Like the inner conductor crimp connection, the materialstrength, diameter, thickness, and elasticity may be considered whenselecting the relative diameters for crimping the outer conductor 134.The crimp portion 206 of the ring connector 130 may include a lengthequal to or slightly larger than the ring sleeve 136 such that asufficient length of the outer conductor 134 may be crimped therein. Insome embodiments the crimp portion 208 of the ring connector 130 mayinclude circumferentially extending grooves 218 extending around itscircumferential outer surface for engagement by the boot seal 140. Thecrimp portion 208 may also include a hole or a pair of holes 220 forinspecting the crimped conductor 134 within the cavity 216. The holes220 may extend through the crimp portion 208 from an outer surface andinto the cavity 216 and may be positioned near a proximal end of thecavity 216. As such, when the conductor 134 is crimped in the cavity216, a portion of the conductor 134 may be visible through the hole orholes 220 and the depth into the cavity 216 of the crimp connection maybe ascertainable to assure sufficient crimp length.

Like the connector pin 112, the ring connector 130 may be constructed ofa bio-compatible conductive material. For example, the ring connector130 may be made from stainless steel 316L or a metal alloy MP35N, forexample. Other materials may also be used and may be selected to providesuitable biocompatibility and conductivity. Additionally, as with theconnector pin 112, the material and dimensions (e.g., relative diametersand wall thicknesses) may be selected to suitably allow for a crimpconnection to the outer conductor or coil 134 that is both mechanicallysecure and also effectively transmits electrical signals.

The outer conductor or coil 134 may be the same or similar to the innerconductor or coil 120. However, the outer conductor or coil 134 mayinclude a diameter larger than the inner conductor or coil 120. Thediameter of the outer conductor or coil 134 may be selected such thatthe inner conductor or coil 120 and the insulator tubing 124 may bereceived therein. As such, the outer conductor or coil 134 may have adiameter equal to or slightly greater than an outside diameter of theinner conductor or coil 120 plus twice the thickness of the insulatortubing 124. In some embodiments, the diameter of the outer conductor orcoil 134 may be selected to allow non-constricted rotation of the innercoil 120 within the insulator tubing 124 for controlling an activemechanism 106 on a distal end 104 of the lead 100, for example. In otherembodiments, the diameter of the outer coil 134 may be more constrictingon the insulator tubing 124 and the inner coil 120.

The ring sleeve 136, like the pin sleeve 122 may be configured forcrimping the outer conductor or coil 134 within the crimp portion 208 ofthe ring connector 130. As shown in FIGS. 9A and 9B, the ring sleeve 136may include sleeve portion 222 and a flare or rib portion 224 forcontrolling the depth within the coil 134 that the ring sleeve 136extends. The sleeve portion 222 may be a substantially cylindricalportion with an outer diameter slightly larger than an inner diameter ofthe outer coil 134. As such, when inserted into a proximal end of theouter coil 134, some frictional engagement between the ring sleeve 136and the outer coil 134 may be provided. The flare or rib portion 224 maybe positioned on the proximal end of the sleeve portion 222 and mayinclude a diameter larger than that of the sleeve portion 222 forabutting the end of the outer conductor or coil 134 and resistingadvancement of the ring sleeve 136 beyond the proximal end of the outerconductor or coil 134. The diameter of the flare or rib 224 may beselected to be slightly less than the inner diameter of the crimpportion 208 of the ring connector 130 so as to avoid inhibiting thepinching or crimping of the coil 134 between the sleeve portion 222 andthe inner surface of the crimp portion 208 of the ring connector 130. Asdiscussed with respect to the pin sleeve 122, the shape of the proximalend of the pin sleeve 122 and the ring sleeve 136 may depend in part onthe type of raw material used to form the respective part. For example,if tubing is used, the proximal end may be flared, while, if bar stockis used, the proximal end may be more square in cross-section orflange-like. Other geometries may also be provided to stop the sleevesfrom overly advancing into the proximal end of the respective coils 120,134.

The boot seal 140 is shown in FIGS. 10A and 10B. The boot seal 140 maybe configured for encompassing the distal end of the ring connector 130and for sealing the ring connector 130 from entry of fluids. Forexample, when the proximal end 102 of the lead 100 is inserted into asocket of an electrical stimulation device, the boot seal 140 mayprevent fluids or other material from entering the socket andinterfering with the ring connector 130 or other portions of theelectrical stimulation device. As such, the boot seal 140, like theproximal seal 114, may include one or more circumferentially extendingribs 144 protruding from its outer surface. The ribs 144 may be adaptedto engage a cylindrical socket and may have an outer diameter at leastslightly larger than the diameter of the socket so as to sealinglyengage an inner surface of the socket and prevent fluids or other matterfrom traveling into the socket and reaching the ring connector 130 orotherwise leaking into the electrical stimulation device.

The boot seal 140 may be relatively long and may provide a grip for thesurgeon or other installer for handling the proximal end 102 of the lead100. The boot seal 140 may include a bore 141 extending from itsproximal end to its distal end and the diameter of the bore may varyalong the length of the seal 140. The proximal end of the bore 141 maybe relatively enlarged to house the crimp portion 208 of the ringconnector 130. Moving distally, the diameter of the bore 141 may bereduced an may be sized just slightly larger than the outer diameter ofthe outer coil 134. Moving still further distally, the diameter of thebore 141 may again be enlarged. In this region, the boot seal may beenlarged due to an outer insulator tubing and for the application of alead label and/or serial number. The proximal end of the boot seal 140may include an inwardly protruding rib 212 for arrangement in the slotportion 206 of the ring connector 130 thereby securing the longitudinalposition of the boot seal 140. Like the proximal seal 114, the boot seal140 may be made from a biocompatible silicone to resiliently engage andseal the lead 100 relative to the electrical stimulation device. Othermaterials may also be used.

Referring again to FIG. 3, the assembled proximal end of the lead may bedescribed. As shown, the electrically conductive connector pin 112 mayextend through and may be rotatably disposed in a center bore 150 of aproximal seal 114 and a center bore 118 of a connector insulator 116.The necked-down portion 164 of the connector pin 112 may be arranged inthe center bore 118 and the electrically conductive inner conductor orinner coil 120 may be crimped to the conductor end 162 of the connectorpin 112 by the pin sleeve 122. The inner insulator tubing 124 may extendover the inner coil 120 and the claw portion 126 thereof may be sleevedonto the distal extension 186 of the connector insulator 116 to abut theinner shoulder 190 of the cascading shoulders and having an outersurface substantially flush with the cylindrical outer surface 127 ofthe inner shoulder 190. As such, the connector pin 112, the crimpconnection, and the inner coil 120 may be substantially fully insulatedalong its length by the connector insulator 116 and the insulator tubing124. However, the inner conductor 120 may be exposed via an electrode atthe distal end 104 for treatment and the connector pin 112 may beexposed at the proximal end 102 for electrical communication with anelectrical stimulation device. The proximal seal 114 may be arranged onthe connector insulator and the outwardly projecting ribs 146 may engagea socket on an electrical stimulation device to prevent fluid or otherliquid from being in contact with the connector pin 112.

The band portion 204 of the ring connector 130 may extend over the clawportion 126 of the insulator tubing 124 and may abut the outer shoulder188 of the cascading shoulders on the connector insulator 116. As shown,the outer surface of the band portion 204 of the ring connector 130 maybe flush with the outer surface 129 of the central body 182 of theconnector insulator 116. The outer conductor or outer coil 134 may bearranged to sleevably receive the inner coil 120 and insulator tubing124. The outer conductor or coil 134 may be crimped to the ringconnector 130 by a ring sleeve 136, thereby electrically connecting tothe ring connector 130. The boot seal 140 may be positioned over theouter coil 134 and an inwardly protruding rib 212 thereof may engage aslot portion 206 of the ring connector thereby securing the position ofthe boot seal 140 relative to the ring connector 130. The crimped outercoil 134 and portions of the ring connector 130 may be disposed within acenter bore 141 of the boot seal 140. Like the proximal seal 114, theoutwardly projecting ribs 144 of the boot seal 140 may engage a socketon an electrical stimulation to prevent body fluid or other liquid frombeing in contact with the ring connector 130 or otherwise entering theelectrical stimulation device.

As shown in FIG. 3, the necked-down portion 164 of the pin 112 mayextend through the center bore 150 of the proximal seal 114. Thenecked-down portion 164 may be separated from the inner surface of thecenter bore 150 by the proximal extension 184 of the connector insulator116. As such, an inner surface 154 of the connector insulator 116 mayprovide rotational bearing for the connector pin 112 such that theconnector pin 112 may rotate relative to the connector insulator 116 andproximal seal 114. Rotation of the connector pin 112 may drive rotationof the inner coil 120, thereby rotating the mechanism 106 disposed atthe distal end 104 of the lead 100. The lead 100 shown may be referredto as an active lead, and the mechanism 106 may be referred to as anactive mechanism. It is appreciated that other suitable rotatableconnection means may be used between the inner coil 120 and theconnector pin 112 without departing from the scope of the presentinvention.

Accordingly, the connector pin 112 may be electrically connected to theinner coil 120, and the ring connector 130 may be electrically connectedto the outer coil 134. In operation of the present invention, electricalsignals may be sent from the proximal end 102 to the distal end 104 viathe connector pin 112 and the inner coil 120, and via the ring connector130 and the outer coil 134. The inner coil 120 may be electricallyinsulated from the outer coil 134 by the inner insulator tubing 124. Thering connector 130 may be electrically insulated from the inner coil 120by the inner insulator tubing 124 and the connector insulator 116. Theconnector pin 112 may be electrically insulated from the ring connector130 by the proximal seal 114 and the connector insulator 116. Theconnector pin 112 may be prevented from being in contact with fluid orother liquid by the ribs 146 of the proximal seal 114. The ringconnector 130 may be prevented from being in contact with fluid or otherliquid by the ribs 144 of the boot seal 140.

FIG. 11 illustrates a cross-sectional view of the proximal end 402 ofone embodiment of the implantable medical electrical lead 400 with thepassive mechanism 406 in accordance with the principles of the presentinvention. The reference numerals used in FIG. 11 correspond to thereference numbers used in FIG. 3 to reflect the similar parts andcomponents, except the first digit of each reference numeral.

Accordingly, in the embodiment shown in FIG. 11, the design of theproximal end 402 of the lead 400 is very similar to the design of theproximal end 102 of the lead 100, except that a connector insulator 416includes a much shorter proximal extension 484. As shown, in detail inFIGS. 12A and 12B, connector insulator 416 may be similar to theconnector insulator 116 in many respects. For example, the central body482 and distal extension 486 may be substantially the same. However, theproximal extension 484 may extends inside the center bore 450 of theproximal seal 414 a shorter distance than proximal extension 184. Incontrast to FIG. 3, the proximal extension 484 shown in FIG. 11 extendspartially through the bore 450, but not fully through the bore 450. Theremaining portion of the bore 450, as shown in FIGS. 11, 13A and 13B,has a smaller diameter that encroaches the outer diameter of thenecked-down portion 464 of the connector pin 412. In this embodiment,rather than allowing for rotation of the pin 412, the connector pin 412may be fixedly connected to an inner surface 456 of the proximal seal414 by medical adhesive or other suitable bio-adaptable adhesiveequivalence. In this embodiment, the connector pin 412 may not be freeto rotate relative to the other portions of the lead 400 and as such,the inner conductor or coil 420 may not be rotated to cause rotation ofthe mechanism 406 disposed at the distal end 404 of the lead 400. Thislead 400 may be referred to as a passive lead, and the mechanism 406 atthe distal end may be referred to as a passive mechanism.

As a result, one of the advantages of the present invention is that mostof the parts and components of active and passive leads can be shared,which significantly reduces the cost of tooling, manufacturing, andassembling. For example, in comparing FIGS. 3 and 11, all of the innerparts 112/412, 122/422, 120/420 and the outer parts 130/430, 136/436,134/434 are the same. The insulator tubing 124/424 is also the same. Thedifference between the parts of FIGS. 3 and 11 include differingproximal seals 114, 414 and the differing connector insulators 116, 416.Accordingly, of the ten parts used to construct the proximal end 102,402 of the active or passive leads 100, 400, two of the ten may bemodified to transition from an active to a passive lead.

These and other features of the present invention will become apparentto those skilled in the art from the above description. As it will berealized, the invention is capable of modifications in various obviousaspects, all without departing from the spirit and scope of the presentinvention. Also, it is appreciated that the configurations, shapes,forms, sizes, materials, and assembly of the above-mentioned leads andthe configurations, shapes, forms, sizes, materials, and assembly at adistal end with a passive or active mechanism can be implemented invarious ways without departing from the scope of the present invention.

What is claimed is:
 1. A proximal end of an implantable lead, whereinthe lead includes a conductor, the proximal end comprises: a unitaryconnector pin having a socket end, a conductor end, and a necked-downportion arranged therebetween, the conductor end having a crimp cavitywith an inner surface a proximal end of the conductor is positioned inthe crimp cavity; and a pin sleeve configured to be received in a spacedefined in the proximal end of the conductor, wherein the proximal endof the conductor is crimped against the inner surface of the crimpcavity when the proximal end of the conductor is positioned in the crimpcavity.
 2. The proximal end of claim 1, wherein the conductor endincludes an inspection hole for ascertaining a quality of a crimpconnection between the conductor and the inner surface.
 3. The proximalend of claim 2, further comprising a connector insulator placed aroundthe necked-down portion of the unitary connector pin; and a proximalseal positioned on a portion of the connector insulator.
 4. The proximalend of claim 3, wherein the proximal seal is isolated from the unitaryconnector pin by the connector insulator.
 5. The proximal end of claim4, wherein the connector insulator is adhered to the unitary connectorpin.
 6. The proximal end of claim 3, wherein the connector insulatorincludes a central body, a distal extension extending therefrom, and aproximal extension extending from the central body opposite the distalextension.
 7. The proximal end of claim 6, wherein the distal extensionincludes a plurality of cascading shoulders.
 8. The proximal end ofclaim 6, wherein the proximal seal is arranged on the proximal extensionand abuts the central body.
 9. The proximal end of claim 8, wherein theproximal extension extends fully through the proximal seal.
 10. Animplantable lead, comprising: a longitudinally extended body having aproximal end and a distal end; a conductor extending from the proximalend to the distal end; a unitary connector pin arranged on the proximalend, the unitary connector pin having a socket end, a conductor end, anda necked-down portion arranged therebetween, the conductor end having acrimp cavity with an inner surface a proximal end of the conductor ispositioned in the crimp cavity; and a pin sleeve configured to bereceived in the proximal end of the conductor, wherein the proximal endof the conductor is crimped against the inner surface of the crimpcavity when the proximal end of the conductor is positioned in the crimpcavity.
 11. The lead of claim 10, wherein the conductor end includes aninspection hole for ascertaining a quality of a crimp connection betweenthe conductor and the inner surface.
 12. The lead of claim 11, furthercomprising a connector insulator placed around the necked-down portionof the unitary connector pin; and a proximal seal positioned on aportion of the connector insulator.
 13. The lead of claim 12, whereinthe proximal seal is isolated from the unitary connector pin by theconnector insulator.
 14. The lead of claim 13, wherein the proximal sealconnector insulator is adhered to the unitary connector pin.
 15. Thelead of claim 12, wherein the connector insulator includes a centralbody, a distal extension extending therefrom, and a proximal extensionextending from the central body opposite the distal extension.
 16. Thelead of claim 15, wherein the distal extension includes a plurality ofcascading shoulders.
 17. The lead of claim 15; wherein the proximal sealis arranged on the proximal extension and abuts the central body. 18.The lead of claim 17, wherein the proximal extension extends fullythrough the proximal seal.